Pneumatic grader.



Unitarian States PATENT OFFICE.

VlLLlAM S. OSBORNE AND ELVIN C. BRYANT, OF ST. LOUIS, MISSOUR.

PNEUMATiC GRADER.

SPECIFICATXON forming part 0f Letters Patent NO. 710,603, dated October 7, 1902.

Application iiledDecemher 17,1900. Serial No. 40,176. (No model.)

.lle it known that we, VILLIAM S. OSBORNE and ELWIN O. BRYANT, citizens ofthe United States, residing at the city of St. Louis, in the State of Missouri, have invented a certain new and useful improvement in Pneumatic Graders, of which the following isafull, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming` part of this specification, in which- Figure l is an elevational View, partly in section, the section being taken on line l l, Fig. 3, of our improved pneumatic grader. Fig. 2 is a vertical sectional view on line 2 2, Fig. 3. Fig. 3 is a horizontal sectional View on line 3 3, Fig. l; and Fig. 4 is a view illustrating a system of pulverizing and grading material, showing our improved grader in said system.

This invention relates to a new and useful improvement in pneumatic graders designed especially for use in connection with systems for pulverizing and grading material, such as shown in an application filed by us contemporaneously herewith on December 17, 1900, Serial No. 40,177, and designated Case A, the object being to separate the particles of pulverized material from air for the purpose of collecting the same either in the form of finished product or as tailings to be returned to the grinding or pulverizing machine.

One of the objects of our present invention is to provide a simple and cheap construction for effecting the separation or grading of pulverized material, utilizing raretied air for the purpose of effecting such separation, the heavier particles falling to the bottom of the apparatus while the lighter particles are carried off. XVe propose using an eXhaust-fan in connection with our improved grader for rarefying the air therein, thus forming a suction on the grinding-machine suilcient to take away and elevate the pulverized material into our improved grader as fast as it is ground and also drawing olii the lighter particles of dust from the grader, the heavier particles being returned to the grinding-machine or collected as a nished product, as desired.

XVith these objects in View our invention consists in the construction, arrangement, and combination ot' the several parts, all as will hereinafter be described and afterward pointed out in the claims.

Referring to Fig. 4, wherein is illustrated a system for pulverizing and grading material, A indicates a machine for reducing material to a finely-divided state, the material to be reduced being fed into said machine through a closed hopper containing a feeding apparatus a. This reducing machine may be of any desirable construction, and we have not, therefore, shown the details of the same in the drawings.

B indicates a spout leading from the top of the machine, into which the reduced material from the machine is received.

h is a valve in the spout B. V

The spout B leadsintowhat we have designated as grader O, the details of which are shown in Figs. l to V3. This grader preferably consists of an octagonal casing having a conical lower portion discharging into a spout l), which spout connects with the feed end of the machine and is provided with a valve d. The top ofthe grader is closed by a suitable cover.

E indicatesa deiiector secured to the grader in advance of the inlet-opening, said deflector being attached at one side and tothe top of the grader, an opening or space being provided at the opposite side and bottom of said deleetor for the passage of the dust-laden air.

In speaking of the dust-laden air we wish to be understood asr meaning the air coming from the grinding-machine, which serves as a vehicle to carry the particles of reduced material in suspension. When this dust-laden air is introduced into the grader C, it strikes the detlector E and is caused to take other than a straight path, being directed downwardly and to one side, so that the heavier particles will fall and the lighter particles will be carried by the air to and through the escape-opening. By reason of the polygonal shape of. the casing eddies are formed, which give to the dust-laden air a whirling motion, which enables the heavy particles to be more readily affected by the greater vacuum in the bottom of the casing. Where two grindingmachines discharge into a single grader, we

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prefer to employ a pipe B and a detlector E', which operate in substantially the same way as above described. However, in this description we will assume that the pipe B is a blind pipe, having a vcap provided at its end.

F indicates a discharge-pipe leading from the head of thegrader opposite the inlet-pipe B, said pipe F being of larger diameter than the inlet-pipe B and connecting with the eye of a fan G. A suitable valvef is arranged in the pipe F.

H indicates a pipe leading from the fan G into the head of a separator I.

In using the term grader in connection with this construction we do so primarily to distinguish this part of our apparatus from the separator. The purpose of this so-called grader is to form a strong suction on the mill, so as to relieve it of the fine and coarse dust before said dust reaches the speed of the beaters in the mill, and when this dust is drawn into the grader to initially grade the pulverulent material, returning the large particles, called tailings, back to the grindingmachine to be reduced and permitting the particles of sufficient neness to pass on beyond the grader. This greatly increases the capacity of the mill. In other words, this so-called grader serves as a screen in that by regulating the valves in the spout of the exhaust-fan it is possible to cause material ot' varying degrees of iineness to be passed therethrough, say, up to a certain mesh, those particles of material exceeding in size the desired mesh being returned to the machine for regrinding or to a suitable receptacle as iinished product. It will be observed that the grinding-machine, operating in a closed system, will thoroughly reduce the material. The vacuum in spout B can be regulated by the valve b. The dust-laden air entering the grader will be deflected laterally and downwardly, the tortuous passage it is compelled to follow forming eddies, causing the dustladen air to whirl, resulting in the precipitation of heavier particles of material into the pipe D, which connects with the feed end of the pulverizer. The outlet-pipe F being of larger area than the inlet-pipe and connected with the eye of an exhaust-fan will have a constant tendency to draw and exhaust all the air and its carried particles of material through the grader. The amount of air admitted to the grader is controlled by the valves b andtl, the available area through which said air is drawn into the fan being controlled by the valve f.

It is well known that particles of material held in suspension in air rely upon the air resistance for their buoyancy; that if said particles of material were placed in a vacuumchamber, wherein the air would offer no resistance to the action of gravity, said particles of material would be practically dead, so far as their floating capacity is concerned. We take advantage of this natural law in effecting the grading action in the chamber C by exhausting the air fromv said chamber and creating a partial vacuum therein, the

greater vacuum being at the bottom of the' wherein there exists a partial vacuum, and

being compelled to take a tortuous passage at the'time of introduction into said chamber, the particles of material will immediately become more susceptible to the action ofgravity when they reach the grading-cham-y ber, and the heavier particles will fall and the lighter particles will he drawn into the pipe F to the exhaust-fan. By regulating the valve d the fineness of the particles entering the pipe F can be controlled. -lt` said valve is closed or nearly closed, it follows that there is no upward circulation of air through the pipe D. Therefore the heavier particles are not resisted in their descent, and a more finelydivided product will thus pass through the pipe F. lf, on the other hand, the valve CZ is open to permit an upward circulation of air therethrough, the particles of material meeting with this resistance are held in suspension by the air passing upwardly through the pipe D, and consequently the material passing through pipe F is ofa coarser quality. ln order to get a fine grade of material, the valve CZ is kept closed, or nearly so, allowing only asuftlcient opening for the discharge of the tailings. The regulation of valve b is such that the opening controlled thereby is about sufficient to take care of the capacity of the grindi'ng machine without admitting an excess quantity of air at this point; but of course itV will be understood that the valve b, being open full, will affect the degree of fineness of the particles of material passing through the pipe F. However, it is not intended to use the valve b for the purpose of accomplishing this, said valve being designed primarily to control the exit-openingfrom the grindingmachine, and thus goes more to accommodating the capacity of said machine than to controlling the quality of ground material passing beyond the grader. The valve fis adjustable to regulate the discharge-opening from the grader according to the capacity of the fan, and while the opening controlled by this valve will affect the quality of material passing therethrough said valve isnot intended to be used for this purpose, we preferring to rely rather on the valve d, which is not only more accessible, but depending upon conditions can be manipulated as occasion requires-as, for instance, an excess of heavy particles falling into the pipe D would require the valve dito be opened to a greater extent to permit of a proper discharge thereof, while a scarcity of material in pipe D would require that the valve tl be closed, or nearly so, to prevent the outside air rushing in. The

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accessibility of valve d and its ease of manipulation is of advantage in the event of an irregular feed of material into the grindingmachine. lf the material to be ground is not regularly fed and there is no regulation of valve d, it follows that a variation in the quality ofthe product will result which is undesirable.

The pipe H, being the discharge-pipe from the exhaust suction-fan G, leads into a separator l, the details of construction of which are not shown in this application, they forming the subject-matter of a separate application tiled contemporaneously herewith on December 17, 1900, Serial No. 40,178, and des-v ignated Gase C. However, we will state that the particles of dust are collected in the separator, being deposited in a spout J, controlled by a valve j, the air containing finelydivided material, which is practically inseparable therefrom, passing through a pipe K into an auxiliary separator 1T, which is provided with a down-spout O, carrying such particles of dust as may be collected in this auxiliary separator back to the fan G. A pipe P leads from this auxiliary separator out to the atmosphere. We do not in this application claim the system above described, and will therefore not go into a detailed description of its operation.

So far as we are aware we are the first to separate or grade particles of pulverized material by the use of eddies in a partial vacuum, which vacuum by being regulated will control the relative amount of fine or coarse material passing through the respective openings,through which the graded material passes from the grader.

We are aware that minor changes in the arrangement, construction, and combination of the several parts of our device can be made and substituted for those herein shown and described without in the least departing from the nature and principle of our invention.

Having thus described our invention, what we claim, and desire to secure by Letters Patent, isy l. In an apparatus of the character described, the combination with a casing having an enlarged head and a tapered lower portion, a substantially tangential inletpipe leading into said head, an outlet-pipe leading laterally from said head at a point approximately opposite and in substantially the plane of the inlet-pipe, a discharge-pipe leading from the lower end of the tapered portion, a valve in said pipe, and a suctiontan connected with the outlet-pipe leading from the head; substantially as described.

2. In an apparatus of the character described, the combination with a casing having an enlarged head and a lower tapered portion, a substantially tangential inlet-pipe leading into said head, an outlet-pipe leading laterally from said head, a deflector E projecting inwardly from the side and top of the casin g for causing the dust-laden air passing from said inlet to said outlet pipe to take a tortuous passage, an outlet-pipe leading from the lower end of the conical portion of the casing, a valve in said last-mentioned outlet-pipe, and a suction-fan connected with the outlet-pipe leading from the head of the easing; substantially as described.

3. The combination in an apparatus of the character described, of a casing having a polygonal-shaped enlarged head, and a tapering lower portion, an inlet-pipe leading into said head substantially in line with one side thereof, a deiiector in the head, joining said side and forming therewith an acute angle directly in the path of the discharge from the inlet-pipe, a discharge from the lower end of the tapering portion, and a suction device for creating a partial vacuum in said head, substantially as described.

et. In an apparatus of the character described, a casing, an inlet-pipe leading into the casing, an outlet from the casing, and a deector forming with the wall of the casing an acute angle directly in the path of the discharge from the inlet-pipe, substantially as described.

5. ln an apparatus of the character described, a casin g, a tangentially-arranged inlet-pipe leading into the upper portion of the casing, an outlet from the casing located in substantially the plane of the inlet, a discharge-pipe at the lower portion of the casing, and a deiiector forming with the wall of the casing an acute angle directly in the path of the discharge from the inlet-pipe, substantially as described.

6. The combination in an apparatus of the character described, of a casing having an inlet-pipe, a deflector in the casing forming with the wall thereof an acute angle in the path of the discharge from the inlet-pipe, and an outlet from said casing located at a point remote from the inlet and beyond the defiector; substantially as described.

7. The combination in an apparatus of the character described, of a casing having an inlet-pipe, a detlector in the casing forming with the wall thereof an acute angle in the path of the discharge from the inlet-pipe, an outlet from said casing located at a point remote from the inlet and beyond the deiiector, and means for creating a partial vacuum in the casing; substantially as described.

S. The combination in an apparatus of the character described, of a casing having an inlet-pipe near its upper end, a deiiector in the casing forming with the wall thereof an acute angle in the path of the discharge from the inlet-pipe, an outlet from the casing at the upper portion thereof located at a point remote from the inlet and beyond the deflector, an outlet from the lower portion of the casing, a valve in said last-mentioned outlet, and a suction device associated with said first-inentioned outlet; substantially as described.v

9. The combination in an apparatus of the character described, of a casing having an en .IOO

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said` last-mentioned outlet, and a suction de-y vice associated With said hist-mentioned outlet; substantially as described.

10. The combination in an apparatus of the character described, of a casing having an inlet-pipe at the upper portion thereof, a deector secured at its end to the casing at one side thereof and projecting laterally there into and in the path of the discharge from the inlet-pipe, an outlet from said casinglocated at a point remote from the inlet and beyond the deliector, an outlet fromthe lower portion of the casing, a valve in said last-mentioned' outlet, and a suction device associated with said first-mentioned outlet; substantially as described.

ll. The combination in an apparatus of the character described, of a casing` having,` an inlet-pipe at the upper portion thereof and an air-outlet, a deflector secured at its end to the casing at one side thereof and projecting lat# erally thereinto and in the path of the discharge from the inlet-pipe,and an outlet from the lower end of the casing; substantially as described.

In testimony whereof we hereunto affix our signatures, in the presence of two witnesses, this 14th day ofDeceinber, 1900.

WILLIAM S. OSBORNE. ELWVIN C. BRYANT.

fitnessesz F. R. CoRNWALL, WM. IL SCOTT. 

